1. Hypothesis Testing for Proportions
Section 7.4
Hypothesis Testing for Proportions
Objective: SWABT How to use a z test to test a population proportion p.

2. Test for 1. Write the null and alternative hypothesis.
A state school administrator says that the standard deviation of test scores for 8th grade students who took a life-science assessment test is less than 30. You work for the administrator and are asked to test this claim. You find that a random sample of 10 tests has a standard deviation of At = 0.01, do you have enough evidence to support the administrator’s claim? Assume test scores are normally distributed.
1. Write the null and alternative hypothesis.
2. State the level of significance.
= 0.01
3. Determine the sampling distribution.
The sampling distribution is c2 with 10 – 1 = 9 d.f.

3. 4. Find the critical value.
5. Find the rejection region.
2.088
6. Find the test statistic.
n = 10
s = 28.8
7. Make your decision.
c2 = does not fall in the rejection region, so fail to reject H0
8. Interpret your decision.
There is not enough evidence to support the administrator’s claim that the standard deviation is less than 30.

4. Homework 1-12 pg.378 Day 2: 13—16 Ex. Cr. 17-18 pg.379